Metal wool pad



Feb. 26, 1963 M. P. MILLER ETAL METAL WOOL PAD 3 Sheets-Sheet 1 Filed Feb. 9, 1959 Feb. 26, 1963 M. P. MILLER ETAL METAL WOOL PAD Filed Feb. 9, 1959 3 Sheets -Sheet 2 Feb. 26, 1963 M. P. MILLER ETAL 3,078,489

METAL WOOL PAD Filed Feb. 9, 1959 3 Sheets-Sheet 3 The present invention is concerned with metal wool pads of the character used on domestic floor polishing machines and intended to be readily attached or removed. Commonly the pads of that type are applied by pressing them onto the flat area comprising the ends of the bristles of the circular brushes and are releasably secured by means of a clip part in the center of the pad which is pressed down and snapped into engagement with a mating spring clip part located in a recess in the center of the brush.

The usual shape and character of that type of pad is a generally flat disk of steel wool and the housewife in mounting it on the polishing machine brush is required to overcome two resisting forces, that is she must deform the pad into the central recess and overcome the spring resistance of the clip. The first is particularly troublesome because the fibers of the pad dig into and interlock with the ends of the bristles and drag the bristles into a bent condition. This deflection of the bristles produces a resilient force on the wool pad which sometimes causes the spring clip to be released unless it is made unusually strong and therefore harder to manipulate. The deflected pad also presents an uneven surface to the floor, reducing the efiiciency of the pad.

Various expedients have been proposed to overcome the above described difficulties such as special clips which,

however, add to the cost and furthermore may become lost and a source of annoyance. In each case the connection must of course be below the working surface to avoid marring of the fioor or other object being polished.

The present invention comprises a pad which is preformed in a simple economical manner to substantially the ultimate shape when applied to a polishing machine. It includes a central dimple or axially offset portion which is comprised entirely of the normal metal fibers but the fibers are more compressed and compacted together therein rendering that portion more firm and self-sustaining, and the annular portion outside the central offset portion remains flat and fluffy and best suited to the butting quality of the pad at the working area. The pad is reversible by merely pushing the dimple or central offset portion through to the opposite side thereby enabling the pad to be used with either side as the working surface.

The dimple described above is an important feature of the invention and is employed to advantage with or without further features concerning strengthening weld lines now to be described. In addition to the compression of the fibers in the offset portion rendering them more compact, the pad in the specific examples disclosed herein is subiected to welding operations through selected areas which add to its stability and strength and maintenance of shape. Particularly the pad is provided with wel lines extending radially from the center outwardly through the central portion and into the outer flat area and preferably to the outer periphery, and an area in the region of the clip is welded together. Preferably the central welded area extends into the area of the central clip which has opposed circular portions in effect riveted together with the thickness of the pad compressed between the opposed parts of the clip. With the clip overlapping the welded sections it is thus securely mounted and impossible to pull loose by normal handling and greater strength and rigidity are obtained. The welded area within and adjoining the clip acts substantially like a States patent ice solid steel washer and eliminates the need of employing auxiliary washers. The radial lines of welding serve as semi-rigid ribs and aid in obtaining and maintaining the desired shape including the offset central portion which is in the nature of a conical part. The pad is nevertheless resilient and the central conical portion may still be pressed through from one side to the other whereby the pad is reversible as has been described above. In this respect it is noted that the degree of welding in the sloping parts of the dimple may be varied to vary correspondingly the flexibility of the dimple and obtain the best combination of strength and reversibility.

The pad is easily and economically manufactured.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a view in perspective of the finished pad;

FIG. 2 is an exploded view in perspective of the parts of a die adapted to shape the initial blank of metal wool;

FIG. 3 is a cross-sectional view in elevation showing the parts of FIG. 2 in assembled relation;

FIG. 4 is a view in perspective of the pad as derived from the operation shown in FIG. 3;

FIG. 5 is a cross-sectional view in elevation showing the pad with a mounting clip attached and applied to a standard rotary brush;

FIG. 6 is a cross-sectional view illustrating the reversibility of the pad;

FIG. 7 is a fragmentary cross-sectional view through the mounting clip in enlarged scale taken on the plane 7--7 of FIG. 6;

FIG. 8 is an exploded view showing the parts of a die adapted to weld certain areas of the pad;

FIG. 9 is a view showing the welding die parts of FIG. 8 in assembled relation;

FIG. 10 shows a pad with the welded areas obtained in the operation pictured in FIG. 9;

FIG. 11 is a bottom plan view of a pad with certain areas welded;

FIG. 12 is a similar view showing a somewhat different arrangement of welded areas;

FIG. 13 is a fragmentary view on an enlarged scale of the central part of the pad of FIG. 11 with a mounting clip secured in place; and

FIG. 14 is a view similar to FIG. 13 but with the mounting clip applied to a pad like that of FIG. 12.

The improved pad indicated at 10 in FIG. 1 is generally of circular disk form composed of an abrasive wool, commonly a metal wool such as steel wool. In accordance with the present invention the pad is shaped to have a central dimple or oitset portion 11 which is generally conical in shape with the base merging into an outer annular portion 12 which is comparatively flat in shape and comprises the working area of the pad. The fibers in the central portion 11 are compressed into a more compacted state than the outer areas as will be described more fully. The outer areas remain generally fluffy. Secured at substantially the peak of the central cone is an appropriate metal clip 13 which is of a type adapted to snap into releasable locking relation with a complemental clip mounted in the central part of the brush of a standard polishing machine. The character of the fastening means may vary according to circumstances but preferably it is of a standard form which commonly is of a glove fastener type comprising male and female elements, one of which is carried by the pad and the other by the brush. In the particular pads illustrated herein the pad carries the female element 13 which is adapted to spring over the male element carried by a bracket in the center of the brush as will be described below. However, these parts may be reversed as will be 4..) readily understood. The details of the clip part carried by the pad are shown particularly in FIG. 7 and comprise a lower part 14 having a tubular extension 15 projecting through a hole in the pad and received in an upper annular part 16 and riveted over at 17 whereby the thickness of the pad is clamped between the two parts of the clip. Each side of the clip carries a split locking ring 18 and 19 respectively adapted to spring over the complemental male clip part carried by the brush.

The pad as shown in FIG. 1 also has welded areas to add to the stiffness and strength comprising the radial weld lines 25 and also a central welded area 26 in the region of the metal mounting clip 13.

The method of manufacture may vary as to details and sequence of steps, but one complete series of operations illustrative of a suitable procedure to derive the desired product will now be described.

Initially the pad blank is made in the usual way, namely the required amount of metal wool is cut from a ribbon and weighed and wound into an appropriately shaped hall. For the application of the mounting clip it is necessary to provide the pad with a central hole which may be punched out in the blank at any suitable stage in the course of manufacture of the pad. The blank of wound metal wool is subjected to pressure between die elements such as the female die part 30 and the complemented male die part 31. These parts are shown in operative relation in FIG. 3 mounted. within a suitable sleeve 32 with the pad 28:: located between the die parts. One or the other of the die parts is movable and pressure is exerted to deform the central portion of the pad. blank. into a dimple or offset portion 33 of substantially conical shape-With a fiat top area 34. The dies are so relatively proportioned that the pressure is exerted principally upon the conical portion compressing and compacting the fibers therein into a relatively firm condition. The conical part 33, therefore, has substantial resilient stiffness, whereas the outer flat portions are compressed only slightly and retain a flat fiuffy condition. FIG. 4 shows the pressed pad derived from the operation in FIG. 3. As indicated above a central hole for the mounting clip is formed at a desired point in the operation and the pad of FIG. 4 has therein such a hole indicated at 35 which may be formed during the pressing operation of FIG. 3 or following that operation or at a later stage as will be noted hereinafter FIG. illustrates the pad as positioned on and fastener. to abrush of a polishing machine after the clip of suitable form such as that shown in FIG. 7 has been secured in the pad. A polishing machine of the character here concerned normally has a pair of brushes like that indicated atdtl in FIG. 5 arranged side by side and rotatably driven. Each brush has within a central recess portion a clip such as that indicated at it to which the clip on the pad is adapted to be snapped into releasable springheld condition. It will be noted that the pad as preformed has a shape conforming substantially to that of the brush 40 including the central recess and is easily applied with a minimum of effort by thumb pressure exerted on the spring clip 13 suflicient to snap the parts together. The working portion 42 of the pad remains relatively flat. If the pad in FIG. 5 were initially a plain pad fiat throughout, the application thereof to the brush it) would require distortion of the bristles and considerably more force to bring the clip parts into interlocking relation, Actually the bristles would be distorted to a progressively greater degree from the periphery into the center and the outer ends thereof and the pad would have a contacting area shaped approximately like that indicated by broken lines 43 and 44 in FIG. 5. Accordingly there would be a constant resilient pressure exerted on the central part of the pad, and the working area of the pad would be distorted from a fiat plain condition resulting in a floor pad with reduced working surface in contact with the floor.

The pad as preshaped has the additional advantage that it is readily reversible and still retains the advantages of being preshaped as above described. FIG. 6 shows in broken lines at 45 the central offset portion shifted by pressure through the center of the pad into the opposite position whereby the pad may be mounted on the supporting brush with the other fiat surface thereof exposed as the working surface.

in accordance with the more complete form of the pad of the present invention, it is provided with welded areas to give added stiffness and firmness to the preformed shape. This is accomplished by suitable welding dies such as those illustrated in FIGS. 8 and 9. The construction may be varied considerably as well as the shape of the weld and the exact areas welded and it will be recognized that the apparatus as shown in FIGS. 8 and 9 is mainly diagrammatic and illustrative. As there shown the apparatus includes a main outer sleeve 5%) in which the die parts are adapted to be mounted, one of which, however, may be stationary such as the die part 51 and the upper die part 52 vertically reciprocable in the sleeve. The bottom die 51 is illustrated as the female part and is provided with upstanding ribs 53 in the shape of a cross with a central cut out area 53:: corresponding to the offset portion of a pad. The upper die 52 is provided with a complemental set of ribs 54 each including a projecting angular part 54a adapted to be received in the central opening of the lower die. FIG. 9 shows the die parts brought into close relation by the exertion of pressure, on the upper die for example, compacting the fibers between the opposed ribs and through the application of electric current Welding the parts together between the opposed surfaces of the two die parts. Such operations are well known in the art and the details are not described or disclosed herein other than to indicate at 56 a source of electric power with connections at 57 and 53 to the respective opposed die parts. The outer sleeve is made of insulating material or at least suitable means are embodied to avoid short circuiting. The opposed ribs must of course be in exact registry which may be accomplished in any suitable way such as by the provision of a tongue do on the reciprocatory die part 52 adapted to be received in the groove 61 of the sleeve 5%.

FIG. 10 shows a pad 62 such as that derived from the operation of the welding apparatus of FIGS. 8 and 9. FIG. 11 also shows a bottom plan view of a typical form of welded pad which may be like that of PEG. 10 and obtained from the apparatus of FIG. 9. As shown the pad has weld lines or bands 63. It will be observed that the weld lines in this case stop short of the central hole in the blank whereby the hole is retained and the clip 67 readily applied as shown in FIG. 13, the clip overlying the weld lines or bands to add to the strength and stiffness of the pad. in order that the weld lines do not extend into the central hole and push metal fibers thereinto and interfere with the application of the clip, the welding ribs of one or both of the dies are cut away at the center as indicated at 68 of the die 51%.. By varying the degree of welding and compression or" the fibers at the weld lines in the sloping sides of the dimple part 62a the degree of stiffness thereof may be varied and the best combination of strength and flexibility for reversing of the dimple obtained. Ordinarily the degree of welding will be less at the sloping sides as is intended to be indicated by the lighter Weld areas 63a in FIG. 11.

FIG. 12 shows a pad 69 with a slightly different arrangement of welded area. In this case the dies are so shaped as to form a welded annular area 76 at the central part which stops just short of the hole '71 leaving a small band 72 unwelded to insure that the hole 71 remains clear for the insertion of the metal clip. A clip applied to this form of welded area is shown at 73 in FIG. 14 in which the welded area extends under the opposed washer parts of the clip and a small radial distance outside the periphery, as indicated at 7 With the welded areas of the character illustrated in FIGS. 12

and 14, the pad under and adjacent the metal clip is provided with a more or less solid welded area for the clip which functions as a rigid part and eliminates the necessity of any auxiliary washer. With the weld thus extending into the area of the clip the pad has greater strength and the fibers can be torn away from the middle portion only by exceptional force.

Other types and shapes and areas of welding may be employed both at the clip area of the pad and in the body portions thereof and it will be understood that the present construction and description are illustrative only of the various arrangements and relations which may be employed in that regard. In the forms shown herein the central hole for the clip was formed in the blank before the welding operations. However, it will be understood that the hole can also be made during the welding operation by including a suitable punch, or after welding by a punching operation. If the hole is to be punched after the welding operation the weld may be made to extend over the entire central area of the pad. Also variations the shaping and welding operations may be employed. For example the forming of the central dimple or offset part may be accomplished simultaneously and as a joint operation with the welding as by dies generally similar to those shown in FEGS. 8 and 9. Alternatively the welding operation may be performed first and the offsetting or" the central portion made thereafter, or in other words a reversal of the order of the steps.

As has been stated above various changes may be made in the above construction and different embodiments of the invention could be made Without departing from the scope thereof, and it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A circular pad of metal Wool fibers having an outer annular generally flat portion and a central axially offset portion, the mass of fibers extending in continuous form from the outer annular portion into said offset portion, the fibers in the offset portion being compacted to a greater extent than the fibers in said outer annular portion and sufficiently that the offset portion is self-sustaining.

2. A circular pad of metal Wool fibers having an outer annular generally fiat portion and a central axially offset portion, the mass of fibers extending in continuous form from the outer annular portion into said offset portion, the fibers in the offset portion being compacted to a greater extent than the fibers in said outer annular portion and sufficiently that the offset portion is self-sustaining, and means in said offset portion for connecting the pad to a support.

3. A circular pad of metal wool having an outer annular generally flat portion, and a central offset portion of generally conical shape extending axially from the general plane of the pad, fibers in said outer portion being in fluffy uncompressed condition and the fibers in said conical portion being compressed to a greater degree providing relatively higher stiffness.

4. A circular pad of metal wool having a shape in general of a disk with a central portion of metal wool extending axially from the general plane of the pad, said portion being generally conical in shape and having the fibers in said portion permanently compressed together to a greater degree than the outer part of the pad for relatively higher stiffness and capable of self-sustainment but having resilience such as to enable the portion to "be pressed to extend in either axial direction.

5. A circular pad of metal Wool having a shape in general of a disk with a central portion of metal wool extending axially from the general plane of the pad, said portion being self-sustaining and with the fibers therein compressed to a greater degree than the outer part of the pad, and a rigid mounting clip secured at the center of said portion, the metal fibers immediately adjacent said clip being welded together.

6. A circular pad of metal Wool having an outer annular generally flat portion and a central portion, each said portion being composed of the metal wool extending axially therefrom, and radial weld lines in said central portion extending outwardly into said outer portion.

7. A circular pad of metal Wool having an outer annular generally flat portion and a central portion extending axially from the plane of said outer portion, the fibers in said central portion being compressed to a greater degree than said outer portion providing relatively higher stiffness, and radial weld lines in said central portion extending outwardly into said outer portion.

8. A circular pad of metal wool having an outer annular generally flat portion and a central portion extending axially from the plane of said outer portion, the fibers in said central portion being compressed to a greater degree than said outer portion providing relatively higher stiffness, and radial weld lines in said central portion extending outwardly into said outer portion, said central portion being self-sustaining as to shape but capable of being flexed through the pad to extend in either axial direction.

9. A circular pad of metal Wool with an outer annular generally flat portion having fibers therein in a generally I fiufiy condition, and a central portion extending axially from the plane of said outer portion, the fibers in said central portion being compressed ot a greater degree than said outer portion providing relatively higher stilfness, the metal fibers being welded together at a central area and along lines extending radially therefrom into said outer portion, and a rigid mounting clip secured at the center of the pad having opposed parts With said central welded area clamped therebetween.

10. A circular pad of metal wool having a central axially extending generally conical portion and an outer annular generally flat portion, a rigid mounting clip secured at the center of said central portion, the fibers of the pad being welded together in radial lines extending from said clip and into said central and outer portions, said conical portion being self-sustaining as to shape but capable of being flexed through hte pad for reversing thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,675,078 Yutzler June 26, 1928 2,319,923 Finnell May 25, 1943 2,439,424 Goodloe Apr. 13, 1948 2,819,478 Sutton Jan. 14, 1958 FOREIGN PATENTS 81,321 Netherlands Apr. 16, 1956 804,354 Great Britain Nov. 12, 1958 895,904 France Apr. 17, 1944 

1. A CIRCULAR PAD OF METAL WOOL FIBERS HAVING AN OUTER ANNULAR GENERALLY FLAT PORTION AND A CENTRAL AXIALLY OFFSET PORTION, THE MASS OF FIBERS EXTENDING IN CONTINUOUS FORM FROM THE OUTER ANNULAR PORTION INTO SAID OFFSET PORTION, THE FIBERS IN THE OFFSET PORTION BEING COMPACTED TO A GREATER EXTENT THAN THE FIBERS IN SAID OUTER ANNULAR PORTION AND SUFFICIENTLY THAT THE OFFSET PORTION IS SELF-SUSTAINING. 